With the development of information and communication technologies, studies have been conducted on various types of interaction methods between human and machine. Among them, an effective input means for a user terminal has been developed. For example, a capacitive touch screen being widely used these days has an advantage of determining whether an input is received through a proximity contact between an input means such as a human finger and the touch screen and executing a command conveniently using the finger, but has a limitation in that only two input activities of a user, that is, a touch and a release, are acceptable, and a disadvantage of limited haptic representations transmittable to the user due to a flat shape and an issue of finger occlusion occurring frequently during interaction with the user due to a relatively small size. To relieve these problems, many researchers have been studying interaction methods through an object such as a stylus pen.
Among these methods, some methods include, for example, pen rolling, pen tiling, touch screen touch type recognition, pen grip type recognition, and the like. A pen rolling technique uses an activity of rolling a pen around an axis of the pen as a mode change command, and similarly, various techniques of selecting a menu based on a tiling angle have been introduced. Also, recently, a pen that recognizes a pen grip type through a multi-touch sensor and executes different commands based on the pen grip type has been introduced. Further, a pen that executes different command based on a touched portion of a display, for example, a corner, an edge, an end, or a side, has been introduced.
However, existing methods discussed in the foregoing often involve an unwanted mode change occurring naturally when a conventional input activity using a pen is conducted. Accordingly, there is a need for a terminal interaction method using an object such as a pen, as a gesture easily distinguishable from a conventional pen input activity.